This invention relates to an instrument for quantifying the interaction between atomic, ionic, and/or plasma jets with solid or liquid materials surfaces. In particular, this invention relates to an apparatus for the measurement of particle, momentum, and energy fluxes of a plasma stream where forces onto surfaces defining the plasma boundary are transmitted by ionic and neutral particles with 10's of eV's of kinetic energy, are accompanied by high heat fluxes, and are pulsed.
Work toward the goal of fusion energy production is progressing in a number of laboratories throughout the world. In the area of magnetic confinement fusion, the major effort is focused on the "tokamak" device, which consists of a toroidal vessel that contains a high temperature plasma, surrounded by magnetic field coils that confine and position the plasma. Design and operation of these devices requires quantitative study of the interaction between an intense plasma stream and surfaces of different materials immersed in dense plasmas.
In the prior art, momentum and energy flows and pressures are calculated using the kinetic theory of gases from measurements of density with ionization, thermocouple, or manometer gauges. The prior art methods are unsuitable, however, for surfaces immersed dense plasmas (n&gt;10.sup.12 cm.sup.-3); little experimental data are available on the effects of ionic impacts, in the energy range &lt;100 eV, onto surfaces; and the theory of plasmas is sufficiently complex (due, for example, to varying collisionality) that single-point measurements of plasma temperature and density in the plasma interior, as by probes or Thomson scattering, do not readily yield an accurate prediction for the particle, momentum, or energy fluxes at the boundaries of the plasma.
It is therefore a primary object of this invention to provide a diagnostic instrument to measure the absolute pressure (momentum flux) from an intense plasma stream where forces onto surfaces defining the plasma boundary are transmitted by ionic and neutral particles with 10's of eV's of kinetic energy and are accompanied by high heat fluxes.
In the accomplishment of the foregoing object, it is another important object of this invention to provide an instrument for measuring momentum flux of a plasma stream in an intense magnetic field and pulsed plasma environment.
It is another important object of this invention to provide an instrument for measuring momentum flux which may be calibrated in situ, without the need to vent to air.
It is a further object of this invention to present an instrument for measuring pulsed momentum flux which gives a response time of approximately 1 ms.
Additional objects, advantages and novel features of the invention will become apparent to those skilled in the art upon examination of the following and by practice of the invention.